Effects of an intermediate layer on the magnetic and recording characteristics of CoCrPtTa media

Effects of bcc and hcp intermediate layers between a bcc-Cr80Ti20 underlaye r and a hcp-CoCrPtTa magnetic layer on magnetic and recording characteristi cs were investigated. The medium without an intermediate layer has a low co ercivity H-c of 0.27 kOe due to the perpendicular orientation of the c axis of the CoCrPtTa layer. By introducing a 5-nm-thick intermediate layer of b cc-Cr60Mo40 or hcp-Co70Cr30, the c axis of the CoCrPtTa layer can be effect ively in-plane oriented, resulting in a high H-c of 2.71-2.87 kOe and a coe rcive squareness S-* of 0.72-0.81. The medium with the Cr60Mo40 layer has l ower media noise than the medium with the Co70Cr30 layer. This lower noise is considered to be caused by the small grain size of 10.4 nm. The addition of the thin Cr60Mo40 intermediate layer is therefore effective to obtain b oth high H-c and low noise in the CoCrPtTa media with the CrTi underlayer. (C) 2000 American Institute of Physics. [S0021-8979(00)49408-9].